Insulin pump systems allow patients to administer safe doses of an intravenous or subcutaneous medication at will, without the need for constant supervision by medical staff. These devices often include a pump housing that houses a cartridge, a motor, a drive system, and a power supply, which supplies power to the motor. The outside of the housing provides key pad entry for allowing the patient to program the rate of insulin delivery and to modify the delivery rate according to the patient's expected or actual carbohydrate intake. Many insulin pumps include a syringe having an insulin reservoir for the delivery of insulin into the patient's body.
The detection of the presence of containers that provide for insulin within the insulin reservoir is a critical functionality for the prevention of accidental injection of insulin during pump manipulation by the patient. In insulin pumps that have reciprocating injection mechanisms, it is required to position the pump injection piston according to the volume of insulin residing in the reservoir being loaded. If the patient instructs the pump to move its injection piston forward at high speed with a filled insulin reservoir still installed within the pump, an accidental injection of insulin may occur. Accidental insulin overdoses may result in severe hypoglycemia, a condition that may have fatal consequences. The ability to detect insulin reservoir presence in a pump may also be beneficial in other instances during pump operation.
Current infusion pump technology utilizes mechanical switches that require mechanical sealing to prevent the ingress of fluid. Since insulin pumps are often used during activities that involve immersion in water such as bathing and swimming, pumps that use such mechanical switching designs are prone to fluid ingress and are often failure points in pumps having these types of mechanical designs.
Given the inadequacies of the prior art techniques used to detect the present of insulin in the insulin reservoir, it would be desirable to provide a method and system that utilizes a non-mechanical design to detect the presence of insulin in the pump's insulin reservoir that does not require a break in the hermetically sealed enclosure of the pump.